CARBON NANOTUBE OR GRAPHENE BASED PRESSURE SWITCH

• US 20120073948A1
• Filed: 09/23/2011
• Published: 03/29/2012
• Est. Priority Date: 09/27/2010
• Status: Active Grant

• Current Assignee: Kulite Semiconductor Products Inc
• Original Assignee: Kulite Semiconductor Products Inc
• Inventors: HURST, ADAM, DEROSA, LOU
• Granted Patent: US 9,455,105 B2
• Time in Patent Office: Days
• US Class Current: 200/81.R
• CPC Class Codes: H01H 2300/036 Application nanoparticles, e.g. nanotubes, integrated in switch components, e.g. contacts, the switch itself being clearly of a different scale, e.g. greater than nanoscale
• CPC Class Codes: H01H 35/26 Details
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

The present invention describes systems and methods for providing a carbon or graphene based pressure switch. An exemplary embodiment of the present invention includes a semiconductor substrate; a cavity defined within the semiconductor substrate having a cross-sectional area and a depth; a bottom conductor disposed within the cavity; a conductive membrane disposed above the cavity and adapted to deflect towards the bottom conductor upon an applied pressure; an elastic, insulating layer disposed between the conductive membrane and the bottom conductor; and a switching element adapted to activate upon electrical communication between the conductive membrane and the bottom conductor.

Claims

1. A pressure switch assembly, comprising:

a semiconductor substrate;

a cavity defined within the semiconductor substrate having a cross-sectional area and a depth;

a bottom conductor disposed within the cavity;

a conductive membrane disposed above the cavity and adapted to deflect towards the bottom conductor upon an applied pressure;

an insulating layer disposed between the conductive membrane and the bottom conductor; and

a switching element adapted to activate upon electrical communication between the conductive membrane and the bottom conductor.

2. The pressure switch assembly of claim 1, wherein the conductive membrane is made from carbon nanotubes.

3. The pressure switch assembly of claim 1, wherein the conductive membrane is made from graphene.

4. The pressure switch assembly of claim 1, further comprising an insulating layer disposed on the surface of the semiconductor substrate.

5. The pressure switch assembly of claim 4, further comprising a top conductor pad disposed on the insulating layer.

6. The pressure switch assembly of claim 1, wherein the insulating layer disposed between the conductive membrane and the bottom conductor is elastic.

7. The pressure switch assembly of claim 1, wherein the insulating layer disposed between the conductive membrane and the bottom conductor is sufficiently thin to allow electron tunneling between the conductive membrane and the bottom conductor.

8. The pressure switch assembly of claim 7, wherein the insulating layer disposed between the conductive membrane and the bottom conductor is made of parylene.

9. The pressure switch assembly of claim 1, further comprising an isolation diaphragm encapsulating the conductive membrane.

10. The pressure switch assembly of claim 9, wherein the isolation diaphragm is made of metal.

11. The pressure switch assembly of claim 9, further comprising an incompressible liquid disposed between the isolation diaphragm and the conductive membrane.

12. The pressure switch assembly of claim 11, wherein the incompressible liquid comprises molecules having sizes that are too large to penetrate the membrane.

13. The pressure switch assembly of claim 1, wherein the cavity has a shape that is substantially rectangular.

14. The pressure switch assembly of claim 1, wherein the cavity has a shape that is substantially circular.

15. A method of indicating whether a pressure exerted by a medium is above a certain threshold pressure comprising:

applying the pressure to a conductive membrane suspended across a cavity, wherein the cavity has a cavity bottom and the pressure causes the conductive membrane to deflect toward the cavity bottom;

creating an electrical potential difference between the conductive membrane and the cavity bottom; and

activating a load when a current flows between the conductive membrane and the cavity bottom;

wherein a substantial increase in the current indicates the pressure is above the threshold pressure.

16. The method of claim 15, wherein the substantial increase in the current is an exponential increase.

17. The method of claim 15, further comprising reversing a polarity of the electrical potential difference to counteract van der Waals'"'"' forces between the conductive membrane and the cavity bottom.

18. The method of claim 15, wherein applying the pressure to a conductive membrane further comprises physically isolating the conductive membrane from the medium.

19. The method of claim 18, wherein physically isolating the conductive membrane from the medium means transferring the pressure to the membrane via an isolation diaphragm and an incompressible liquid.

20. The method of claim 15, further comprising setting the threshold pressure by adjusting a distance between the conductive membrane and the cavity bottom.

21. A method of manufacturing a pressure switch comprising:

providing a substrate;

fabricating a cavity within the substrate wherein the cavity has a cavity bottom;

depositing a conductive material on the cavity bottom;

electrically isolating the conductive material on the cavity bottom;

disposing a conductive membrane across the cavity; and

defining contact pads on top of the conductive membrane;

wherein the depth and geometry of the cavity correspond to a desired threshold pressure of the pressure switch.